1. Field of the Invention
The present invention generally relates to methods of manufacturing a cathode ray tube and, more particularly, is directed to a method of and apparatus for injecting and recovering slurries in the process for making a phosphor screen.
2. Description of the Prior Art
When a phosphor screen of a color cathode ray tube is produced, so-called slurries, such as phosphor slurries of respective colors, carbon slurries, PVP photosensitive liquid, PVA photosensitive liquid or the like are injected into a panel in response to the respective processes, are uniformly coated on the whole surface of the panel, and then extra slurries within the panel are recovered.
In the prior art, as shown in FIG. 1, a panel 1 is located so as to face the inner surface thereof upwardly and a desired slurry 3 is injected through an injection nozzle 2 into the inner surface of the panel 1 (see FIG. 1A). Then, the panel 1 is rotated on its own axis (in the direction shown by an arrow a in FIG. 1B) so as to spread and coat the slurry 3 on the entire surface of the panel (see FIG. 1B). Thereafter, the panel 1 is revolved (in the direction shown by an arrow b in FIG. 1C) such that the corner portion of the panel 1 is faced downwardly to thereby exhaust extra slurry 3 from the panel 1 (see FIG. 1C). The panel 1 is then rotated on its own axis (in the direction shown by an arrow a) so as to urge the slurry of a desired film thickness to be coated thereon (see FIG. 1D). Thus, the coating process of slurry is finished.
According to the above conventional method in which the desired slurry 3 is injected into the panel 1, the panel 1 is revolved (in the direction shown by the arrow b) and then the panel is rotated on its own axis (in the direction shown by the arrow a in FIG. 1D) to provide the slurry of desired film thickness thereby removing the extra slurry 3 from within the panel, the slurry 3 is considerably scattered to the surroundings and the surroundings are contaminated.